Conventional semiconductor processing equipment includes four parts: source cabinet 11, furnace module 12, load station 13, and controller 14, as shown in FIG. 1. Furnace module 12 contains an inner horizontal quartz tube 101 and outer horizontal quartz tube 101a for processing wafers. The outside wall of the outer horizontal quartz tube 101a is surrounded by heating elements 102 for heating wafers loaded inside it. Wafers are placed on the top of the boat 105 and delivered by the trolley 103 into horizontal quartz tube. Source cabinet 11 contains gas piping (not shown in FIG. 1) and a mass flow controller (not shown in FIG. 1). At the close end of inner horizontal quartz tube 101, an inlet pipe 106 of a gas injector introduces N.sub.2 gas into the horizontal quartz tube. At the left side end of outer quartz tube (reference to FIG. 1), an opening 106a introduces reaction gas into the horizontal quartz tube, such as, O.sub.2, H.sub.2, or POCl.sub.3 and so on. Controller 14 controls the factors of processing wafers, such as, temperature, timing, air, and recipe.
FIG. 2A shows the loading station of a conventional furnace module with inner 201 and outer 202 horizontal quartz tubes. A trolley 200a with slide bearings is set on parallel slide shafts, and two boats 203a are put on a base boat 203, which is placed on the trolley. Wafers 210 are placed on the boats 203a of the trolley, and then loaded into the horizontal inner quartz tube 201 of the furnace module through the opening 201a of the inner quartz tube 201. In the front section of the inner quartz tube 201 near the opening of the tube, there is a breach 201a at the bottom of the tube. After the wafers are loaded into the inner quartz tube, the whole inner quartz tube 201 is encased by the outer quartz tube 202, and then the process of semiconductor is performed. FIG. 2B is a cross-sectional view of the inner quartz tube 201. In the front section of the inner quartz tube 201 near the opening of the tube, there is a breach 201a at the bottom of the tube. Therefore, the base boat 203 loaded with wafers (not shown in FIG. 2B) can be moved into the inner quartz tube 201 through the breach 201a.
FIG. 3A shows the top view of a conventional trolley. Referring to FIG. 3A, two stages 301 with two quartz bars 302 are respectively fixed on a base plate 303 which is placed on a holding plate 300. The quartz bars are used for preventing the base boat contacting with the stages 301. An altitude adjusting screw 304 is used for adjusting the altitude of base plate 303. After the altitude of the base plate 303 is adjusted, a first fixing screw 305b is used to fix the altitude adjusting screw 304. A plurality of second set of fixing screws 305 are used to fix the base plate 303 on the holding plate 300, and a plurality of third set of fixing screws 305a are used to fix the two stages 301 on the base plate 303. A loading rod 306 is used for lifting the base plate 303 from the trolley by turning it. FIG. 3B, a cross-sectional view of the conventional trolley, shows connections among the base plate 303, holding plate 300, and main body 311 of the trolley. The altitude of the holding plate 300 is adjustable by turning the altitude adjusting screw 304, and the holding plate 300 and main body 311 of trolley are connected by a plurality of supporting pillars 312.
FIG. 3C shows the bottom view of the conventional trolley 300. A plurality of fourth set of fixing screws 305c are used for fixing the trolley with the main body 311, and a position hole 307 is used for locating the trolley on the supporting base. FIG. 3D, the right side view of the conventional trolley, demonstrates the position which the wafers and boats 310 are placed on.
FIG. 4A shows the top view of a supporting base of the conventional trolley. A plurality of fourth set of fixing screws 405 are used for fixing the top plate 400 of the supporting base on the slide bearings, and a position pin 409 is used to locate the trolley by the position hole 307 shown in FIG. 3C. FIG. 4B shows the cross-sectional view of the supporting base of the conventional trolley. The slide bearings 408 are fitted with two parallel slide shafts 410, so as to be allowed moving back and forth in the axial direction of the slide shafts. FIG. 4C shows the right view of the supporting base of the conventional trolley.
Using the conventional trolley to load the wafers into the horizontal inner quartz tube has some disadvantages. For example, since the trolley supporting base is nearby the furnace module, users may get hurt due to the high temperature of furnace module. In addition, the trolley is not easy to locate on the trolley supporting base. Further, the contact area 411 (Showen in FIG. 4A) between the trolley and the trolley supporting base is relatively small, so the boats and the wafers placed on the trolley are easily oscillated and turned over during the time of loading wafers.